Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Strategy for destroying a 6 km wide asteroid

  1. Jan 23, 2009 #1
    What do you think is the best statergy for destroying a 6 km wide asteroid which is heading towards the earth.

    Do you think it is possible to develop "clean fusion Nucs" which can be deployed from spacesations to intercept such a large asteroid

    also if a fusion bomb were to fall appart in space ( not explode) would their be any fallout? i am pretty sure no fallout is produced though.
     
  2. jcsd
  3. Jan 23, 2009 #2
    Re: Asteroids

    If a 6km asteroid is heading for earth fall out is the least of your worries. Personally I don't want any nukes in any space stations.
     
  4. Jan 23, 2009 #3
    Re: Asteroids

    If Im not wrong, the current strategy now is to utilize gravitational pull to swerve the asteroid out of its crash course with earth. Maybe this will be achieved by having a rocket move in close proximity with it. Blowing up such a huge asteroid may not be such a viable idea as the smaller fragments may not disintegrate up in the atmosphere.
     
  5. Jan 23, 2009 #4
    Re: Asteroids

    Stand your ground and whack it back again with a huge tennis racket otherwise call up Bruce Willis.
     
  6. Jan 23, 2009 #5
    Re: Asteroids

    let the asteroid hit the earth, the asteroid will then be pretty much destroyed.
     
  7. Jan 23, 2009 #6

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    Re: Asteroids

    You need to change its momentum vector so that it's trajectory misses the Earth. Considering its size and probable velocity, its going to be pretty tough to generate enough force to change that very much.

    The best strategy is to intercept it early, when even a tiny change in the direction of the asteroid's momentum vector results in it missing the Earth. The closer it gets to Earth, the more impossible the task is going to become.

    Blowing the asteroid up only works if you're sure that will result in most of the pieces missing the Earth. You're still going to have some pretty significant pieces still headed for Earth, but maybe they'll only wipe out a bunch of highly populated cities on a coast instead of the entire Earth.

    For any interception that would be likely to succeed (whether your definition is saving the entire population or just a majority of the population), fallout from any device used would have virtually no impact on the Earth. At that distance, only a miniscule amount of the device's particles would wind up in a trajectory that would return to Earth.

    If you have the mass and have the speed, plus can get some idea of how fast an intercepting vehicle could travel, and know how much advance notice you have, you could figure out how much force the device is going to need - or realizing that amount of force is impossible to achieve, you could figure out how much force you could generate and then figure out how much advance notice you need.
     
  8. Jan 23, 2009 #7
    Re: Asteroids

    I'm no expert on 6 km wide asteroids, but here are some thoughts on 5 km wide asteroids.

    The further away from earth an asteroid is, the more time you have to deal with it. For instance, if the asteroid is 5000 feet above NYC, then knocking it out with a 50 gigaton thermonuclear weapon is a bad idea. If the same asteroid is 5000 feet above Paris, then maybe. But if it is further away, say it won't be coming by for another decade or so, then you have more options. Perhaps you could attach a solar sail to it so that a decade's worth of solar wind would alter its trajectory just enough to veer past the earth. However, as I understand it, the only time you can calculate an asteroid's trajectory that minutely is in physics 101 textbook problems. In the real solar system, the various bodies exert tiny gravitational influences that add up after ten years. There is no closed solution for the resulting many-body problem. Your sail may just nudge that asteroid's trajectory into the Earth. So, the best thing to do is to buy asteroid insurance. Here you are in luck. I sell a policy that pays a tidy sum if an asteroid hits the earth and all life disappears. I am no stickler for details when it comes to premiums, you can send me any amount you like.

    Now, multiply all this by 6/5 and your problems are solved.
     
  9. Jan 23, 2009 #8

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    Re: Asteroids

    The best strategy is to have about a 100 years notice. Then you have Congress solve the problem and don't worry about it. While they're at it, they can increase social security benefits and medicare benefits.
     
  10. Jan 23, 2009 #9
    Re: Asteroids

    I have difficulty believing even a large nuclear device would blow something that size to pieces. Rather, I wonder if the devices were planted some distance underground if they wouldn't blow out enough material to provide a little thrust in another direction.

    It seems to me there are only two places where such a bomb could be located - the two places where the axis of rotation intersects the surface. Presumably one would be better suited than the other.
     
  11. Jan 23, 2009 #10

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    Re: Asteroids

    I only included that because there seems to be some kind of myth that you can blow something up in space and not have to worry about the orbits of the debris. For example, ASATs that break-up a satellite are usually really bad ideas since you've created hundreds of new ASATs that intersect your own satellites' orbits.

    Thinking about it a little more and using real asteroids, the problem is a little different.

    An extraordinarily large number of asteroids greater than a 100 meters have slow rotation rates - less than whatever rotation rate would send any loose material off into space due to centrifugal force. Solid objects could rotate faster. They could also rotate slower, but having so few rotating at fast rates suggests that most asteroids are accumulations of loose debris rather than solid bodies. It might not take as much force as one would think to break them up. Of course, you'd still have to worry about the orbits of the debris. In fact, you'd have some maximum limit of force you could use to even change the orbit without breaking up the asteroid.

    A real asteroid wouldn't be very far away. They have orbital periods of about 4 1/2 years. Ideally, you'd predict when the asteroid's orbit would intersect the Earth several years in advance. That would give you an interesting trade-off between the rotational axis and the direction of travel. The rotational axis should be close to perpendicular to the orbit plane, although I think that would be even less certain than for the planets. Changing the asteroid's inclination at apohelion would be the best long term solution with the added advantage of a thrust along the rotational axis. The orbit would then pass below or above the Earth. I think changing in-track velocity would be the most energy efficient if you could use pulsed thrusts to compensate for the rotation. That would only change the orbital period, though, and the asteroid could still hit the Earth years later.
     
  12. Jan 23, 2009 #11
  13. Jan 23, 2009 #12
    Re: Asteroids

    I would just put some jam in your pockets, cause your about to be toast.
     
  14. Jan 23, 2009 #13
    Re: Asteroids

    Even if you managed to veer an asteroid off the collision cource it can still come back and collide some other time ( in orbit). I also heard of some gravity key holes that must be passed otherwise the asteroid will come around again. By the way would a nuclear blast produce a show wave in space or are stuff more likley to simply get burnt?
    I suppose it will depend on the asteroid as well. It would be interesting to explode a nuc in space to see its effect - as long as the bomb runs only on fusion ( clean Nucs)
     
  15. Jan 23, 2009 #14

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    Re: Asteroids

    No, a nuclear blast doesn't create a shock wave in space (see the link by OAQfirst). The blast does create an Electro Magnetic Pulse that wipes out tons of electronic equipment (in space or on Earth, provided it's in line of sight of the explosion). They tested this in the 60's. Not a great weapon since it wipes out everyone's unprotected equipment, not just the enemy's.
     
  16. Jan 23, 2009 #15

    wolram

    User Avatar
    Gold Member

    Re: Asteroids

    Beatles, Beatles beat Stones, and if asteroids are stony then the Beatles will over power them ,just make sure you paint the rocket yellow and put a penny on the hood.
     
  17. Jan 23, 2009 #16

    Kurdt

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Re: Asteroids

    Get that little white triangle thing to deal with it.

    [​IMG]
     
    Last edited: Jan 23, 2009
  18. Jan 23, 2009 #17
    Re: Asteroids

    Clearly the only way to deal with it is to open a small hyperspace window so that the asteroid passes through the earth.
     
  19. Jan 24, 2009 #18
    Re: Asteroids

    What do u think is worse the enhanced green house gass effect or the threat of asteroid impact
     
  20. Jan 24, 2009 #19

    Evo

    User Avatar

    Staff: Mentor

    Re: Asteroids

    Automobile accidents are worst.
     
  21. Jan 24, 2009 #20

    LowlyPion

    User Avatar
    Homework Helper

    Re: Asteroids

    I trust that you don't have any recent experiences that are troubling you.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Strategy for destroying a 6 km wide asteroid
  1. Risk Strategies (Replies: 14)

  2. Strategy for minesweeper (Replies: 32)

  3. Destroy earth (Replies: 31)

  4. Destroyed in seconds (Replies: 22)

Loading...